Compressor-turbine engine



B. G. CARLSON COMPRESSOR-TURBINE ENGINE Filed April so, 1945 2 Sheets-Sheet l N mc w TL 0 m w mm A a M T E 5 V. B a m Q l. v Qua R om Iv ow mu 5 Oct. 25, 1949.

B. CARLSON COMPRESSOR-TURBINE ENGINE 2 Sheets-Sheet 2 Filed April 30, 1945 INVENTOR. BERT G. CARLSON A TOIENEYS mm NH Patented Oct. 25, 1949 UNITED STATES PATENT OFFICE COMPRESSOR-TURBHVE ENGINE Bert G. Carlson, Gates Mills, Ohio Application April 30, 1945, Serial No. 591,145

.6 Claims. 1

The presentinvention relates generally to engines of the combined compressor-turbine type, and more particularly to engines of this type having novel compression and explosion chamber construction and greatly improved emciency.

Heretofore engines have been proposed in which a gas turbine and compressor were axially v mounted on a common shaft within a housing. The compressor drew air into the housing and forced it into a combustion space between the compressor and turbine. Fuel was introduced into that space and ignited and the heated gases were passed thru the turbine and rotated the shaft and compressor. The air which was delivered into the combustion space was not highly compressed, particularly at the lowersrotational speeds of the shaft, and about half of the expansive forces of the burning gases was opposed to the flow of air thru the compressor. The efllciency of these engines was relatively low, on the order of possibly 35%. As the rotational speed of the shaft increased the rate of flow of air increased with corresponding increase in back pressure on the air and, as a result, the emclency increased only to a limited extent over that at the lower speeds.

Moreover, these engines equipment for starting. When the starter was mounted on the vehicle, it added to the weight of the vehicle and occupied space which could have been used for other purposes, and when the starter was kept on the ground, the vehicle engine could be started only where such a starter was available. Such an arrangement precludes starting the engine of an airplane while in flight. Various proposals have been made to increase the efiiciency and avoid other disadvantages of combined compressor-turbine engines but many of these proposals have involved complicated structures and high loss of efficiencies. So far as I know, none of these proposals has proven to be sufficiently efficient to be satisfactory for general use.

The present invention aims to provide a combined compression-turbine engine which is simple in construction, is highly efiicient in operation, is easy to start without the aid of an auxiliary starter, is easy to control, is adequately cooled and may utilize either the rotational forces of the shaft or the jet propulsive forces of the gases or both of these forces. My invention provides an eflicient compressor-turbine engine which may be used as a stationary engine or as a mov ing engine. may be coupled with an air or water screw 50 as require auxiliary When used as a moving engine, it.

to utilize the shaft rotating forces of the gases and also the jet propulsion efiect of the gases. When used as a stationary engine, it utilizes only the shaft rotating forces of the gases.

An important feature of the present invention is the provision, between an air compressor and gas turbine, of an air compression chamber, an explosion chamber, and means for periodically connecting 'those chambers for flow of compressed air from the compressed air chamber into the explosion chamber. tures of the invention are the provision of a hollow shaft which may be cooled by the flow of air therethru; a shell surrounding the engine and defining therewith a space which may be cooled by the flow of air therethru; and the mounting;

of the shaft on bearings located in the relatively cool compressor. v

The present inventionrwill be better understood by those skilled in the art from the following description and the accompanying drawings which illustrate embodiments of the present invention and in which Figure 1 is a central, sectional view, partly in elevation of an airplane engine embodying one form of the present invention and equippedwith an air screw;

Figure 2 is a transverse; sectional view taken on line 2-2 of Fig. 1 and showing means for starting the engine and for supplying fuel thereto;

Figure 3 is a front end elevational view of the engine of Fig. 1'; and,

Figure 4 is a side elevational view, partly in central section, showing a modified form of the engine of Fig. 1.

The engine shown in Figs. 1, 2 and 3 has a the restriction of passage 2 to a point near its discharge end.

Shaft 6 extends along the axis of passage 2 and I is mounted for rotation on radial bearings I and thrust bearings 8. These bearings are carried by hubs 9 which are connected to housing I by webs lli. Shaft 6 is provided wtih a set of compressor blades II and a set of turbine blades l2 which cooperate with the sets of compressor and turbine Other important fea-- blades on the housing in the conventional manner, that is, the fixed blades on the housing are spaced apart axially from each other and the blades on the shaft are positioned to rotate be tween the fixed blades. Fan blades l3 in the shaft 6 serve to propel cooling air thru the shaft.

Between the adjacent ends of the sets of compressor and turbine blades, wall [5 extends inwardly from housing I and lies closely adjacent to a correspondingly shaped wall I6 which extends outwardly from shaft 6. As shown, walls I 5 and iii are spherical in shape. These walls cooperate to form a partition in the passage 2 and to define, in conjunction with the shaft 6 and housing I, an air preheating and compression chamber I! on the intake side of those walls and an explosion chamber i8 on their exhaust side. Each of the walls l5 and i6 is provided with a plurality of apertures I9, in this instance two, to connect chambers I1 and I8 for the passage of compressed air from the former into the latter. It will be understood that when the shaft is rotated, air is compressed in chamber i! when the apertures 19 are out of registry with each other and that such compressed air may flow into chamber it when the apertures are in registry; and also that the expansive forces of gases in chamber I8 can be opposed on the air in chamber I! only during the time apertures are in registry.

A fuel reservoir 20 (Fig. 2) is connected thru suitable piping to a tubular ring 2| which has a plurality of outlets 22 thru which fuel may be delivered into explosion chamber l8, and also thru a bypass to an outlet in the explosion chamber. As Fig. 2 shows, reservoir 20 is connected to ring 2| by piping 25 which includes a filter 25, a pump 21, a pressure regulator 28 and a speed control valve 29. When the engine is in normal operation fuel flows from reservoir 20 to ring 2i thru parts 25 to 29 inclusive, the fuel pumped by pump 2'? in excess of that passing thru valve 29 being returned from regulator 28 to reservoir 20 thru pipe 30. When the engine is to be started fuel flows from reservoir 20 thru pipe 25, filter 25, pump 27, bypass 3|, primer 32, ballcheck 33, and into chamber l8 thru outlet 33. which is exposed to gases in explosion chamber I8 may be connected to battery 36 thru switch 51, the other side of the battery being grounded thru cable 38 to the engine. An air screw til is mounted on the leading end of shaft 6. If desired a shaft connected to a water screw may be operatively connected to and actuated by shaft 6. The fuel pump 21 is carried by web ID of housing i and is driven by gear 5! keyed to shaft 5. An ad ditional stand by pump may be mounted in web iii if desired.

Housing i is surrounded by a shell which is spaced outwardly from the housing to define, with the outer surface of the latter, a cooling space 53. At the forward end of the engine, this shell is provided with intake openings 65. The trailing portion of the shell has a plurality of sections 55 which are connected thereto by pivots t6 and each of these sections is pivotally connected to bi-metallic U-shaped members 61, the inner ends of which are pivotally connected, as at 48, to the housing. These members 41 are responsive to temperature variations and tend to straighten out from the shape shown, as their temperatures increase, thereby moving sections 45 about their pivots 45 and affording exhaust spaces thru which heated air may flow from space 43.

The area of the exhaust end 4 of passage 2 is enough greater than the area at any point for- A spark plug.

wardly thereof to permit such a decrease in pressure as will result in the maximum jet propulsion effect of the hot gases. When the engine is to be used as a stationary engine, the area of the is provided with another web structure 54 which carries a radial bearing 55 anda thrust bearin 55. The housing 50 is surrounded by an air cooling casing 51 having air intake passages 58 similar to passages 44 of Fig. 3, and outlet passages 59 generally similar to intake passages 58. This casing is also provided with pivoted sections 60 and bi-metallic controllers 5| therefor, these sections and controllers being similar to parts 45 and. d1 of Fig. 1. Housing 50 is provided with a plurality of removable, fixed compressor blades 55 and turbine blades 66, the compressor blades being disposed within the space beginning near the intake end of the housing and extending to a point near the preheating and compression chamber I1, and the turbine blades beginning just beyond explosion chamber i8 and extending to a point near the exhaust end of the housing. The blades are seated on cylindrical surfaces 57 and at their trailing sides bear against shoulders 68 of housing 50. Similarly, turbine blades 66 are seated on cylindrical surfaces 69 and at their leading sides bear against shoulders 10 and are held in assembled position by ring H.

Shaft 15 is hollow and open at both ends and is mounted in bearings 52, 53, 55 and 58 located in the compressor part of the engine. A plurality of compressor blades 16 with intervening spacers 11 are fitted onto shaft 75, the spacers being radially aligned with blades 55, and blades it being disposed to pass between fixed blades 65 when the shaft rotates. The collar I8 threaded onto the leading end of the shaft presses the blades '16 and spacers 11 into close engagement with each other and against collar 19 which abuts a shoulder on shaft i5. Thus the blades l6 and spacers H are clamped together for simultaneous rotation with shaft 15 and rotational and thrust forces of theshaft and its blades and spacers are taken by bearings 52. 55, 55 and 55.

The turbine blades BI and spacers 82 are similarly mounted on shaft 15 and are held in place for rotation with the shaft by ring 83 which is screw threaded onto the trailing end of shaft i5 and presses the blades and spacers against the shoulder 84 on shaft 15.

The apertured partition wall 85 corresponds to wall is of Fig. 1 but is integral with collar I I9 which acts as an abutment for the trailing blades F6 of the compressor. Wall 88 is like wall l5 of Fig. 1. A fuel or oil pump M is carried by web 5i and is rotated as by gear 9| which surrounds and is keyed to shaft 15.

The compressor and turbine blac on shaft 15 and spacers I1 may be air cooled b the flow of air thru passages and 95 in the walls of shaft I5 and leading into the interior of the blades and spacers.

Engines embodying the present invention may be started without difliculty by resorting to use of the bypass apparatus shown in-Fig. 2. The

I tuation of primer 32.

speed controller 29 is actuated to shut off any flow of fuel therethru to ring 2|, switch 31 is closed, and fuel from pump 21 is admitted into the explosion chamber by repeated, manual ac- At each such actuation a small quantity of fuel is delivered thru outlet 33 and is ignited by spark plug 35 with resultant production of burning expanding gases and rotation of the shaft. Such repeated injection of small amounts of fuel and the burning thereof in the explosion chamber will quickly heat the walls of that chamber to a temperature at which the combustible mixture will ignite without the aid of the spark and will increase the speed of rotation of the shaft and the compression of the air by the compressor. When the temper ature of the explosion chamber walls rises to a point sufficiently high to ignite the fuel injec- -tions without the aid of spark plug 35, switch 3'! may be opened and speed controller. 29 may be actuated to permitfue1 to flow therethru into ring 2| and thence into the explosion chamber. The speed of the engine may be controlled easily by actuating controller 29 to admit more or less fuel. It will be understood that when an engine is being started in this manner there will be intermittent explosions at first but, as the speed of the shaft increases these explosions will take -makes such auxiliary starting means unnecessary.

It will be understood from the drawings and the foregoing description thereof that engines embodying the present invention may be constructed of a small number of simple parts which are easily assembled and disassembled; that the shaft as well as the housing may be efi'iciently cooled; and that the shaft bearings are protected from the high temperature of the burning gases by being positioned in the relatively cool compressor where they are subjected to the cooling effect of air flow past them. It will also be understood that the unique provision of a preheating and compression chamber in which air is highly compressed and periodically admitted into an explosion chamber thru apertures of smaller area than the compression chamber insures higher engine operating efliciency, as contrasted with previously proposedengines of this general type in which the air stream flows continuously from the compressor to the turbine and is at comparatively low pressure. It will be understood, as aforestated, that during the time the shaft is rotating the movable partition wall between the points where apertures I9 of the two partition walls are not in overlapping position, air drawn into the housing by the compressor will be compressed in chamber l1 and its pressure will thereby be increased considerably, also its temperature will be increased during normal operation of the engine by reason of heat transfer thereto from the explosion chamber. When the apertures l9 are in overlapping position, such preheated and compressed air will flow at high velocity into the explosion chamber where it will instantly ignite.

In prior engines of the compressor-turbin type, about half of the expansive forces of the burning fuel constantly opposed flow of air thru the compressor. In engines embodying the present invention the expansive forces of the burning fuel are only intermittently opposed to the flow of air thru the compressor, that is, when passages l9 are in registry, and even then the pressure so applied to the air is much less due to the small ratio of the area of passages IE! to the area of the compression chamber l1. When passages I9 are out of registry, all the expansive forces of the burning fuel are applied to the turbine. As a result the air is more highly compressed, the energy of the gases is applied to a greater extent to the turbine, and greater efflciencies are obtained.

Having thus described the invention so that others skilled in the art may be able to understand and practice the same, I state that what I desire to secure by Letters Patent is defined in'what is claimed.

What is claimed is: a

1. An engine of the compressor-turbine type comprising a housing having a passage therethru, a rotatable shaft in said passage, a set of compressor blades on the shaft and housing extending rearwardly from the intake end of said passage, a set of turbine blades on the housing and shaft extending forwardly from the discharge end of said passage, an apertured wall extending inwardly from said housing, an apertured wall extending outwardl from said shaft, said walls lying close to each other and constituting a partition across said passage, said partition defining the discharge end of a compression chamber open at the inlet end of said passage in front of said compressor blades and the inlet end of an explosion chamber open at the discharge end of said passage beyond said turbine blades.

2. An engine of the compressor-turbine type comprising a housing having a passage there thru, a rotatable shaft in said passage, a set of compressor blades on the shaft and housing extending rearwardly from the intake end of said passage, a set of turbine blades on the housing and shaft extending forwardly from the discharge end of said passage, an apertured wall extending inwardly from said housing, an apertured wall extending outwardly from said shaft, said walls lying close to each other and constituting a partition across said passage, said partition defining the discharge end of a compression chamber open at the inlet end of said passage in front of said compressor blades and the inlet end of an explosion chamber open at the discharge end of said passage beyond said turbine blades, bearings for said shaft supported by the housing at each end of said sets of compressor blades, and means to deliver fuel into said explosion chamber.

3. An engine of the compressor-gas turbine type comprising. a housing having a passage therethru, a hollow shaft rotatably mounted in said passage, a set of compressor blades on the shaft and housing extending rearwardly from the intake end of said passage, a set of turbine blades on the housing and shaft extending forwardly from the discharge end of said passage, a pair of apertured, overlapping, adjacent walls on the housing and shaft between the said sets of compressor and turbine blades, said walls constituting a partition across said passage and defining in part a compression chamber and an explosion chamber on the intake and exhaust sides thereof, respectively, means to deliver fuel into said explosion chamber, and means comprising air pas- .s ages thru the walls of the shaft and blades on the shaft for cooling said blades.

4. An engine of the compressor-gas turbine type comprising a housing having a passage therethru, a shaft rotatably mounted in said passage, a set of compressor blades on the shaft and housing extending rearwardly from the intake end of said passage, a set of turbine blades on the housing and shaft extending forwardly from the discharge end of said passage, an apertured wall extending inwardly from said housing, an apertured wall extending outwardly from said shaft, said walls lying close to each other and constituting a partition across said passage, said partition defining the discharge end of a compression chamber open at the inlet end of said passage in front of said compressor blades and the inlet end of an explosion chamber open at the discharge end of said passage beyond said turbine blades, means to deliver fuel into said explosion chamber, and 'a shell surrounding said housing and defining therewith a, space having intake and exhaust openings for flow of cooling gas therethru.

5. An engine of the compressor-gas turbine type comprising a housing having an axial passage therethru, a hollow shaft in said passage, a compressor comprising a set of compressor blades'on the shaft and housing extending rearwardly from the intake end of said passage, bearings for said shaft supported by said housing in said compressor, a turbine comprising a set of turbine blades on the housing and shaft extending forwardly from the discharge end of said passage, an apertured-wall extending inwardly from said housing, an apertured wall extending outwardly from said shaft, said walls lying close to each other and constituting a partition across said passage, said partition defining the discharge end of a compression chamber open at the inlet end of said passage in front of said compressor blades and the inlet end of an explosion chamber open at the discharge end of type comprising a housing having a passage therethru, a shaft rotatably mountedin said passage, a compressor comprising a set of compressor blades on the shaft and housing extending rearwardly from the intake end of said passage, a turbine comprising a, set of turbine blades on the housing and shaft extending forwardly from the discharge end of said passage, an apertured wall extending inwardly from said housing, an apertured wall extending outwardly from said shaft, said walls lying close to each other and constituting a partition across said passage, said partition defining the discharge end of a compression chamber open at the inlet end of;s.aid passage in front of said compressor blades and the inlet end of an explosion chamber open at the discharge end of said passage beyond said turbine blades, means for starting said engine comprising means to deliver small amounts of fuel periodically to said explosion chamber, andmeans to ignite such fuel in said chamber, and means for supplying fuel substantially continuously to said explosion chamber when the engine is running.

BERT G. CARLSON.

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